To set this up you will set the two angles equal to 180° since it is a straight line
This will make the equation x+6x+19=180
Combine like terms. 7x+19=180.
Subtract 19 from both sides. This will make it 7x=161
Divide both sides by 7. That will make it x=23
Next plug in the x to solve for abc. 7(23)+19. This equals 157
X= 23
Hope this helped :)